Is the average number of daily calls even 5? The poorest are probably not on the high end of that distribution in any case. It also doesn't need to be applied t

Is the average number of daily calls even 5? The poorest are probably not on the high end of that distribution in any case. It also doesn't need to be applied to regular mobile numbers - just VOIP numbers. At the call volumes these spammers use there is no way they are using diverted SIM/mobile numbers. Another solution is to make the call cost $0.05 or some nominal cost unless the call duration is longer than 20 seconds. Or make calls that are unanswered cost more, etc.